Variable leverage door lift device



Nov. 18, 1941. J. J. oLEKslw VARIABLE LEVERAGE D'ooR LIFT DJvIcE` 2Sheets-Sheet l Il if INVENTOR :I0/els a. @dg ATTORNEY df-ame Filed Nov.1, 1939 gli... x

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J. J. OLEKSIW VARIABLE LEVERAGE Doon LIFT DEVICE Nov. 1s, 1941.

Filed Nov. l, 1939 2 Sheets-Sheet 2 door travel.

Patented Nov. 18, 1941 VARIABLE LEVERAGE DOOR LIFT' DEVICE Jerome J.Oleksiw, Shamokin, Pa., assigner to American Car and Foundry Company,New York, N. Y., a ,corporation of "New Jersey y Application November i,1939, serial No. 302,297 s Claims. (el. iis- 99)l This invention relatesto doors in general and in particular to sliding doors which arenormally held by frictional engagement with their track but may beraised on an antifriction device for horizontal sliding movement.

The majority of lift devices for sliding doors have had the forceapplied to the mechanism in a single direction regardless of thedirection of A very few of the lift devices, however, have been made inwhich the force as applied to lift the door was in the direction of doormovement, but in any case a definite fixed leveragewas utilized. Thisfixed leverage was sulcient to enable the average operator to lift thedoor under average conditions, but in case the door was frozen in placeor the parts had become rusted, then it became impossible for theaverage operator to lift the door. It is an object, therefore, of thepresent invention to provide a door lift ydevice with the parts soarranged as to give a constantly varying leverage.

A further object of the invention is the pro- .Vision of an improvedroller lift device in which the leverage varies from an inm'te value toa nite value, limited only by the ratio of the lengths of the links use.

A still further object of the invention is the provisionof a variableleverage door lift device in which the force applied to the handle tolift the door is always inthe same direction as that toward which thedoor is tov be slid and will at 'some point be 'equal ltothe forcenecessary to cause the sliding movement of the door.

AYet another object of the invention is the provision of avariableleverage door lift device in which the lowering motion of the raiseddoor causes thedoor to rock toward the direction it has been moved,Vthat is, to rock toward closed and sealed position during'lowering andafter vthe door has been slid into substantially closed' more clearlydisclose the construction;

Fig. 2 is a sectional lview taken substantially -online 2-2 of'Figure 1;

Fig. 3 is -aplan view of the lift mechanism with the door housing beingshown in section;

Fig. 4 is a view similar to Figure 1 but showing the door in araisedposition; i

to bottom rail 8.

Figure 1 but showing a modification of the construction; 1

Fig. 6 is an elevational view of the construction shown in Fig. 5 butwith the parts in door raised position;

Fig. 7 is an elevational sectional view taken substantiallyon line 1 1ofFig. 8 and showing a still further modication;

Fig. 8 is a sectional View taken substantially on line 8-8 of Fig. '7but with the roller housing incomplete;

Fig. 9 is a plan view of theroller carriage used in the construction ofFigs. 7 and 8, and

Fig. 10 is an elevational view of a small Vportion of the door bottomrail disclosing the manner in which the door is mounted on the rollercarriage construction of Figs. '7, 8 and 9.

Referring now to the drawings in detail, it will be seen that themechanism' has been applied to a `more or less conventional freight cardoor having a corrugated central panel 2 welded or otherwise secured tofront stile 4, rear stile 6 and In the form illustrated this bottom railis of downwardly facing channel form having its inner and outer flangesor legs I0 and I2 terminating in inner and outer reanges I4 andIii-respectively adapted to normally rest in frictional engagement withan angular shaped track I8. It is, of course, obvious that any type ofdoor may be used and that any type of bottom rail may also be used, butthe type shown is preferable since it fully houses the lift mechanismand prevents entrance of foreign matter.

The door as shown in Figures 1 to 6 inclusive is mounted upon a rollercarriage consisting of an intermediate connecting bar 20 joined at itsends by rivets or other means 2| to straps 22 oiset as at 24 andextended to receive therebetween a roller 26 rotatably mounted upon axle28., The straps 22 are preferably oiset upwardly intermediate their endsin order that the bar 2D may be located as low as possible, thuslowering the center of gravity of the carriage and at the v45v same timeproviding clearances for the motion of themechanism. Each strap 22 ispierced intermediate its ends in order to receive pin 30 extendingbetween the straps and rotatably carrying thereon a link 32 as clearlyshown in Figures 1 to 4 inclusive. The lower end of this link isnon-rotatably connected by means of pin or rivet 34 to a transverse pin36 journaled at its ends in the downwardly directed flanges I0 and I2 ofthe bottom rail. One ofthese latter trans- Fig. 5 is apartialelevational view similar V1;() '55 verse pins may be made square asclearly shown in the left hand portion of Figures 1 and 4 and isextended outwardly beyond the flange l'2 of the bottom rail and hasattached rigidly thereto an operating handle 40. This construction maybe readily assembled by inserting the carriage cornplete with links intothe bottom rail, after which the pins 36 are inserted and fastened bythe pin or rivet 34 andv the operating handle secured to the transverseshaft which extends outwardly beyond the bottom rail.

The operation of the construction shown in Figures 1 to 4 is believedobvious, but assuming" the door to be in lowered position of. Figure 1`it may be raised to the position shown in Figure 4 by merely applying aforce to the handle 4.0 in the direction toward which the door is to bemoved. It should be noted that with the handle 40 vertical and at thestart of the lifting motion the leverage is infinite and constantlyvaries as the handle is swung, that is, as the handle 40 starts itsswing the Amoti-on of the pins 36- is tangent to the track and as itreaches the end kof its travel the pins are moving substantiallyperpendicular to the track. Iii-other words, the effective lever armbetween the fulcrum 30 and. point.` of weight application 36 varies.from zero .to the length of' link .32 if this lin-k is moved tov aihori- Zonta] position, while` the length ot the lever arm between thepoint of forceapplication` and the yfulcrurn remains constant;

In other words, the leverage wi-ll vary from an infinite to a finitevaluelim-itedby the ratio of. the lengths; of. the links-used: Ingeneralpractice, however'it isnot necessary toprovide rfor, such anextremeliftof. the door and accordingly thecarri-ageY maybe designed asillustratedand in this case the minimum nite. 'leverage i-sl limited bythe; swing obtainable before; pin 36 strikes. the straps 2-2. It will'bey seen from liigir-reflV that as the door isY moved toward. a: closedposition and then lowered that. thedoor will'. rock forward toward afurther closed; position duri-ng the; lowering. ofV thev door; such a.motion: being dueto the; relation of the partsand to the fact that thefriction` of the door on its pins is less than'. the

i friction between the carriage and track.

Irr the form shownby Figures 5l and 6 the maior portions are identicakwith thatV just` described in connection with Figures l to. 4s andaccordingly thesame. reference numerals: will.' be: used',A In` thisform, howeven, tvvo.v holes. IIZfareV made in each strap.. and joined byan: opening 43., thus'. providingawindow like opening having two bearingportions in the lower surface thereof. Thelinks 32 are also providedwith two holesf adaptedf. to receive. twto transverse pins; M... Except:for-.the changelin: the mounting of' the. links 512ir this modificationis4 exactly the same. as that.: previously` described and will beassembled. andA operated in. the same manner. vHowever, there isA this.difference, theleverage varies from a small finite; value. to anincreasednite value dependent upon: theratio of theflengths` of thelinks or upony theiswingperniitted the` pinA 3.6'. .The value `ofi thelower. nite leverage wil-l1 be dependent uponthe distance the pins lili.are-placed err.ei'tllier-*side'oiv the center line through the links; Bythis arrangementsof oifset pinsa greater Athrowl or litt may belobtainedwithout necessitatinga great changeains the.l antifriction carriage,.the initial rotation-f starts about a'.v pin oiisetgironr the. centerline,.not about a pin. on thez center.' liner- ..A j

In therorm shownirr "I: to:Y 1'0 inclusive i an. independentroller: 5Uused.jnurnaled on a transverse pin 521 resting at its ends im the; sidewalls of a roller carriage 54. The inner wall of this roller carriage isformed with a projecting trunnion 56, while the outer wall is alsoprovided with a projecting trunnion 58 formed integral with an operatinghandle 60. It should be noted that the trunnions 56 and 58 are offsetrelative to the roller axis or axle and accordingly lany rocking motiongiven the handle will tend to rotate the axle about the trunnions 56 and58. Theentire unit may be readily inserted in the bottom rail of thedoor by lifting the unit into position with trunnions 56 and 58 passinginto vslots 62 and 64' formed respectively in the inner and outerflanges of the door bottom rail. Application of force to the handles inthe direction of desired' door movement will automatically raise thedoor and no conscious lifting effort may be exerted by the operator.

In` each of the forms described application of force to the operatinghandle in the direction of desired door movement automatically applies apowerful leveragefto lift the door and this leverlage varies constantlydecreasing with increased doorliftl It will be obvious that regardlessofthe proportioning of the parts there', will be some point. at which;the force applied to the handle wiil= be sufficient tof'cause the doortoroll on the track and; this point will only be reached after the.)door has, been lifted a slight amount on the carriage or roller' for',as previouslystated; the

leverage decreases .either from an infinite' or extremely/small; finitevalue..v By making; the leverage variablevaaiyoperator will be able toexert an extremely powerful lifting leverage on the door torbreakfytheseal between theV door and car and vto: break any ice or othermatterthat may be preventing the lift iof the door;

.While the; constructions shown have been described; more: or less indetaily it. will heobvious l that, various modifications,rearrangements-of partsl and"'changes. in construction rsuggestthemselves to: persons. skilled in the art and. all 'suchmodiii'cations, rearrangements of parts and changesrrconstruction'arecontemplated as Will tall within the scope of the appended' claims whichdefine my invention.

- Whatisclaimedis: Y f

1f. Ini a lift'd'evice for sliding doors having the bottom portionnormally rest-ingY ona' supporting track;l the combination offen`anti-"friction carriage, suspension links hanging from said carriageandconnected-L adjacent theifr lower -erids' to bottom portion normallyresting on a supporting track, thefcombinatiorijoi" an anti-friction`ldevice including a frame and spaced' rollers, suspension links hangingvfrom said frame. and connected adjacent their. lowerfen'ds to the.lowerA portion or the door 'thereby suspending the. croori on.' saidframe, 'and' an operating handle.V connected to a vertical plane commontov-both. whereby a-,variable leverage may be'exertedyronthe door tolift the same khiring Y shifting. of the, handles,

3=.. In a.; lif-tdevice forvslidi-ngA doors having a 3 bottom portionnormally engaging a supporting track, the combination, of.anti-friction: cai:-

riageg, suspension links; rockablyj supported. ad-

jacent their upper ends on said carriage, means supporting said door instable equilibrium on said links adjacent the lower ends thereof, and anoperating handle secured to at least one of said last named means.

4. In a lift device for sliding doors having a bottom portion normallyengaging a supporting track, the combination of a carriage mounted onanti-friction rollers, means suspended on said carriage and normallysupporting said door at points beneath the carriage in stableequilibrium, and an operating handle rigidly connected to saidsuspension means.

5. In a lift device for sliding doors having a bottom portion normallyresting on a supporting track, the combination of a carriage mounted onanti-friction rollers, suspension means connected to said carriage andsupporting said door at points beneath the carriage, and an operatinghandle rigidly connected to said suspension means, said suspension meansbeing Connected to the carriage by spaced trunnions located on each sideof a vertical plane through the door support points.

6. In a lift device for sliding doors having a bottom portion normallyresting on a supporting track, the combination of a carriage mountedadjacent its ends on rollers, a plurality of suspension links trunnionedon said carriage intermediate said rollers, means connecting the lowerends of said links and door, and an operating handle rigidly connectedto at least one of said last named means and the adjacent link to rockthe latter about its carriage trunnion.

7. In a lift device for sliding doors having a bottom portion normallyresting on a supporting track, the combination of a carriage mountedadjacent its ends on rollers, a plurality of suspension links trunnionedon said carriage intermediate said rollers, means connecting the lowerends of said links and door, and an operating handle rigidly connectedto at least'one oi said last named means and the adjacent link to rockthe latter about its carriage trunnion, said last named means andtrunnion for each link being located substantially in a Vertical planecontaining the trunnion axis.

8. In a lifting device for sliding doors having a bottom portionnormally 'engaging a track, the combination of an anti-frictioncarriage, suspension links hanging from said carriageV and connectedadjacent their lower ends to the lower portion of the door therebysuspending the door on said carriage, an operating lever connected tothe lower portion of one of said suspension links to shift the same,said lever extending in the same direction as the link to Which it iscon nected and the relation of said link and lever being such thatinitial predetermined lift applied to said lever will result indis'engaging said door from said track and further movement of saidlever will cause said door to move in th'e direction of the levermovement.

JEROME J. OLEKSIW.

